Camera track structure



Dec. 25, 1951 A, E, LITTLE 2,580,309

CAMERA TRACK STRUCTURE Filed Feb. 2, 1949 2 SHEETS-SHEET l l 29 INVENTOR.

Dec. 25, 1951 A, E, lTTLE 2,580,309

CAMERA TRACK STRUCTURE Filed Feb. 2, 1949 2 SHEETS-S-IEET 2 Patented Dec. '25, 1951 CAMERA TRACK STRUCTURE AlfreaE. Little, chicago, 1u.,- assignor to Busch Precision Camera Corporation, Chicago, Ill., a corporation of Illinois Application February 2, 1949, Serial No. 74,119

, 1 Claim. (Cl. 95-46) This invention relates generally to a structure for camera tracks which are adapted to slide relative to a camera bed for adjusting the focus of a camera.

The type of camera with which this invention is concerned includes a lens carried by a standard which is movable relative to a track. After the lens is i'lxed to the track, such as for example in opening the camera from a folded condition, the track is adapted to be adjusted relative to the bed of the camera by means of a gear and rack mechanism. The position of the camera lens standard relative to the track is capable of being xed fora given set of conditions whereby an indicator carried by the track may properly read vfocal distance in cooperation with indicia xed relative to the camera bed. Wear of the operating parts of the mechanism and backlash between the gear and rack portion thereof will result in a misadjustmentvof the index. In the event that the track is loosely mounted upon the bed, the lens standard may n'ot be perfectly parallel with the photographic film. or may result in bad photography due to Vshaking of the lens standard, etc.

I The primary object of the invention is to correct all of the above faults and render the track ii-rmly pressed to the track guides during the entire life of the camera.

Still a further object of the invention is to provide for means for automatically taking up the wear between the moving parts of the camera track and its mounting.

Still a further object of the invention is to provide a camera track structure in which the track is resiliently mounted.

Still-a further object of the invention is to provide a. camera track having a pinion and rack mechanism in which the shaft carrying the pinions is mounted upon springs in order to take up backlash and wear and to provide a firmy connection with the rack at all times.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel features of construction, arrangement and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly:

or sacrificing any of the advantages of thein-V vention.l

For 'the -purposeof facilitating-an understanding of this invention, there is iuustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following de-w scription, this invention, its mode of construction, assembly and operation, and many of its advantages should be readily understood and appreciated.

Referring to the, drawings in which the same characters of reference are employed to indicate corresponding or similar parts throughout the several gures of the drawings:

Fig. 1 is a side elevational view of a bellows type camera having my invention associated i therewith.

Fig. 2 is a sectional view taken through the camera bad vand track on the line 2-2 of Fig. 1 andlooking into the direction indicated.

Fig. 3 is a similar view but taken on the line 3-3 of Fig. l.

Fig. 4 is a fragmentary sectional view taken along the line 4 4 of Fig. 6 in the direction indicated.

Fig. 5 is a sectional view taken along the length of the camera bed at the line 5 5 indicated in Fig.2.

Fig. 6 is a top plan view of the camera bed and track mechanism with a portion of the track' removed to show certain'details.

Fig."7 is a perspective view of the pressure bar member which presses against the bottom of the track.

Fig. 8 is a perspective view showing the camera 1 bed with all of the mechanism removed therefrom;A v l Referring now to the gures, the reference character I0 designates generally a camera of the graphic type and comprising a camera body- II, a rear wall I2 covered by a plate holding device I3, which may have a viewing screen associated therewith. 'The front wall I4 of the camera is provided with hinges I5 pivoted at I6 to the bottom of the camera body II; so that thev said wall I4 may open to form the bed of the lens standard in a manner to be described. The camera includes a bellows I'I secured to a lens standard I8 which carries the lens and its housing indicated generally at I9.

The wall I4 which will hereinafter be termed the bed, is provided with integrally formed pivot ears 20 to which there is pivoted the link 2I secured to the camera body I I in order to -iix the position of the bed I4 relative to the body I I whensaid bed is arranged perpendicularly thereto.v The lens standard I8.is mounted upon a base member 22 by means of a sliding dove-tail connection indicated generally at 23 whereby said standard may be moved transversely of the bed I4 by means of a thum-screw 24. Said base member 22 is in turn provided with ared iianges 25 along the lowermost edges thereof which fdanges 25 are adapted to slidingly engage within the rabbets 235 formed in the track rails 21 as best shown in Figures 3 and 4.

The track rails 21 are approximately the samel length as the bed I4 and are of uniform crosssection throughout. The rabbet 25 faces inwardly so that the flanges 25 dove-tail thereinto. Said track rails 21 are integrally formed with front and rear interconnecting cross members 28 and 29 as shown in Fig. 6. An aligned track (not shown) is provided within the camera body II so that when the camera is in closed condition the base 22 is engaged upon the camera track within the body II. When the Acamera is opened the operator grasps a clamping device indicated diagrammatically at 3l] in Fig. l between his iingers, releases the base 22 from the track within the body II, slides same iorward of the camera and onto the track rails 21, releasing the clamping device 30 -when the base 22 has been properly positioned as desired upon the rails 21.

The track member which is indicated generall-yas 3l and which consists of the said track rails"` 21 and the cross Ymembers 28 and 28 is adapted to be moved along the bed I4, to the right and left as viewed in Fig. l, carrying the lens -standard I8 therewith. The purpose of this is to enable precise focusing while the carnera is being'used to photograph objects. The track moves relative to retaining strip guide members 32 which are fixed relative to the bed I 4. By means of cooperative-indicia (not shown) carried by the side rails 2l and said guide members l32 the focal distance for any set of conditions can be determined, providing the lens standard It has been properly positioned rela-f tive to the track member 3I. Moreover, by ad# justing the position of the track relative to the camera bed I4 while viewing the image, for eX,- ample, on a ground glass screen associated with the device I3 it is possible to obtain accurate focusor said image.

Referring now to Figs. 6, 'I and 8 the camera bed I4 `is provided about its edges with ya klip .35 adapted to seat within the open face of the caraera body Il. The portion of the bed I4 within the lip 35is dished downwardly as viewed in Fig. 8 and as shown especially in the sectional views of Figs. 2, 3 and 4. The dished formation gives rise to downwardly slanting portions 38 and the central horizontal portion 31 which is considerably below the lip 35. Integrally formed with the bed I4 at the juncture of the portions 38 and 31 are formations indicated generally at 3,3 which extend along the length of the bed l I4 parallel with opposite edges thereof and inwardly placed therefrom. Said formations 33 each consists of a vertically arranged strip 38 provided along its upper edge with -a shoulder 39 rand hav,- ing a recess 49 provided near the front thereof for a purpose to be described. Spaced from and parallel with the strips 38 are additional strips 4I, 42, 43 and'44 all in alignment and having their vertical extent on a level with a shoulder 89. In terconnecting portions 45, 48 and 41 are pro? vided as'shown in Fig. 8 for the purpose or" strengthening the strips and as well to provide anchoring for certain fastening means presently described. :For this latter purpose each of the portions 45, 46 and 41 is drilled and threaded as indicated at 48. It will be noted that between the strips 42 and lll there is provided a space 49 in alignment with the recess 40 of the strip 38.

` The strip members 42, 43 and 44 are intended for the purpose of posititoning the pressure bar 5G relative to the track rails 2l. For this purpose the pressure bar, which is shown in its entirety in Fig. '1, is provided with ol'set parallel guide members 5I, 52 and 53 equally spaced from the pressure bar 58 and connected thereto by means of the necks 54, 55 and 58 respectively. The neck 54 is intended to be engaged within the space 51 :formed between the ends of the strips 42 and 43, whiie the necks 55 and 56 are engaged between the ends of the strips 43 and 44 as shown in Fig. f5. Obviously the pressure bar members and the construction of the strips 38, 4I, 42, 43 and 44 lare identical on opposite sides of the bed I4, albeit both face inwardly. Each of the necks 54, and 'de are thickened to form a spring housing as indicated at 53, 58 andv ,68 and each housing is bored out to form a cylindrical cavity as shown at 6I. It will be noted that the upper edge 82 of the pressure bar 50 is placed above the upper edges or" the parallel guide members 5I, 52 and so that when the track member 3| is engaged by the pressure bars 5G there will be no interference between the guide members 5I, 52 and 5 3 and any other parts.

In the assembled condition coil springs 84 are disposed within the cavities 5I so that the bottom ends thereof engage the dished portion 31 as viewed in Fig. 5 while the upper ends of said springs are engaged against the bases of the cavities 8l. The length of said springs is such that the pressure bar 50 will have itsy edge G2 disposed at a higher level than the normal level of the track member 2| where same is adapted to engage said pressure bar edge.

Referring now once more to Figs. A2, 3 and 4 note that veach of the track rails 21 has a ilange .along its outer edge and at the bottom thereof. Said flange has a lower horizontal bearing surface 66 and an upper slanting bearing surface 81. The upper surface `81 on each of the flanges slants downwardly and away from the `rails 21 of the track member 3l. The retainer vmembers 32 are provided with cooperatively slantingedges adapted to engage the bearing surfaces 81, said retainer members 32 are engaged upon the shoulders 39 and upon the upper edges of the strip members 4I, 42, 43 and 44. Same are held inthis position bymeans of screws 89 which engage within the abovereferred to screw threaded openings 48. n assembly the track member v3l.

is pressed downwardly vso that the vbearing -Surfaces E8 engage the bearing edge 62 of the surface bars 58 pushing same downwardly and thereby compressing the springs 84 so that the track member 3| is thereby resilientlyv mounted upon springs. Although three of the springs 64 are shown at each side with their cooperating housings and cavities it should be obvious `that any number of such springs could be used. Obl viously as the camera track 3l is slid relative l to the retaining member 32, any wear that occurs between the bearing surfaces 81 and the edges of the retaining members 32 will immediately be taken up by the upward pressure of the springs t4. Also, by reason of the slanted connection between said bearing surfaces 81 and the inward edges of the retainer member 32 the sliding connection will always be firm and without play.

...The track rails 21 .are each ,farmed with a 49, resting upon springs I housed in recesses l 'I6 provided in the bed I4 at these points. When the track member 3| is assembled upon the bed, it is obvious that the springs bearing against the bushing 34 will press the gears 'II against i.

the racks 'I0 and thereby prevent play and taking up wear.

The camera bed I4 is provided with cut out portions 80 and 8I in the forward portions of the dished portions 36 as shown in Figs. 6 and 3. The right hand reduced diameter portion I3 has a thumb screw 82 secured thereto by a set screw 83 as indicated in Fig. 3 while the left hand reduced diameter portion I3 has a attened portion B4 and has the eXtreme end thereof screwthreaded as indicated at 85. A thumb screw 85 having a center opening of the same shape as the reduced diameter portion 'I3 and the flat portion 84 is disposed upon the portion 'I3 and adapted to slide axially thereof but preventedl from rotating relative thereto by reason of the flattened portion 84. A locking nut 8l is screw-y threaded upon the end 85 so that by turning ther locking nut 81 the shaft 'I2 may be locked in any position thereby fixing the camera track member 3| relative to the bed I4 as desired.

It will be seen that I have provided a camera track mechanism which is capable of ontlasting similar mechanisms heretofore used by reason of the ability of my structure to take up wear and play of the moving parts thereof. It should also be noted that by means of my new construction accurate presetting of focus is obtained and as well more satisfactory photographic results can be obtained.

It is believed that this invention, its mode of construction and assembly, and many of its advantages should be readily understood from the foregoing without further description, and itshould also be manifest that while a preferred embodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of widev variation within the purview of this invention as defined in the appended claim.

What is claimed and desired to secure by Letters Patent of the United States is:

In a camera track structure, means for slidably supporting a track upon a camera bed comprising a pair of parallel vertically arranged strip members secured to the bed along the length thereof and having strip guide members secured to their respective upper edges, said strip guide members being in bearing engagement with upper surfaces of the track, a plurality of vertically arranged strips spaced from and parallel with said strip members, said strips being secured to said bed, a pair of elongate pressure mernrs parallel to said strip members, a plurality of guide inembers offset and equally spaced from said pressure members and having necks connecting the same to said members respectively, each of said strips being engageable with an associated guide member whereby to conne said pressure members against motion parallel to the bed, but permitting motion perpendicular thereto, housings integral with said pressure members and having downwardly opening cavities, coil springs loosely confined in the cavities and having their lower ends bearing against the cameral bed whereby resiliently to support said pressure members and space same from the bed, said pressure members engaging the bottom of said track and thereby pressing the upper surfaces or said track into engagement with said strip guide members.

ALFRED E. LETTLE.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,524,289 Christie Jan. 27, 1925 2,293,438 Liebmann et al. Aug. 18, 1942 2,376,416 Campbell May 22, 1945 2,449,156 Wittig Sept. 14, 1948 FOREIGN PATENTS Number Country Date 13,242 Great Britain of 1908 107,245 Austria Sept. 10, 1927 

